The present invention relates to a multi-spindle automatic lathe adapted to continuously process a plurality of workpieces while rotating them in an indexing fashion, and more particularly to such a lathe for the purpose of improving the processing efficiency and reducing the overall dimensions of the lathe.
In a continuous processing operation for rod-shaped workpieces where a plurality of tools is exchanged consecutively, a multi spindle automatic lathe has been used, wherein the lathe comprises a spindle carrier mounted so as to be freely rotatable in an indexing fashion relative to a head stock, and a plurality of spindles each of which is mounted to be freely rotatable about the indexing rotation center of the spindle carrier and has a workpiece loaded thereon respectively.
Each workpiece is loaded on the respective spindle of the multi-spindle lathe and is processed simultaneously at each of the work stations provided corresponding in number to the number of spindles. Upon the processing operation for a workpiece being completed at each of the stations, the spindle carrier is rotated in an indexing fashion so that each workpiece may be processed sequentially at a plurality of work stations.
The construction of such multi spindle automatic lathes in the prior art will be described in detail hereinbelow, with reference to FIG. 4 which illustrates the concept of such automatic lathe, and FIG. 5 which illustrates its spindle carrier in a cut-away view.
Illustrated in these drawings are a head stock 101 for the multi-spindle automatic lathe and a spindle carrier 102 which is mounted to be freely rotatable in an indexing fashion relative to head stock 101. A driving shaft 105 extends through the center of the spindle carrier 102 via bearings 106 to be freely rotatable relative to the head stock 101 and the spindle carrier 102. The above-described driving shaft 105 is coupled with a driving motor (not shown) via a reduction gear 104 which is incorporated in a column 103.
The above-described spindle carrier 102 is provided with a plurality of hollow spindles 107 each of which surrounds and is arranged to be parallel with the driving shaft 105.
A spacing between the driving shaft 105 and each of spindles 107 is designed to be equal with a spacing between each of adjacent spindles 107, and the rotary indexing angle of the spindle carrier 102 for every run is designed to correspond with the number of the spindles 107 to be mounted on the spindle carriers 102.
Fixed at the rear end of the driving shaft 105 is a driving gear 109 which may simultaneously engage a follower gear 108 fixed at the rear end of each of the spindles 107, and all of the spindles 107 are made to be rotatable in the same direction as the driving shaft 105 is driven to rotate.
Additionally, a circular rod-like workpiece W which penetrates through each of the spindles 107 and has its distal portion to be processed extended beyond the tip end of the spindle 107, is supported in position on the spindle 107 by means of a collet 110 attached to the spindle 107 respectively.
In each of the work stations in number corresponding to the number of the spindles 107 to be attached, there is arranged a cross tool slide 111 movable in a direction (i.e., in a upper and downward direction in FIG. 4) in which it may intersect with the driving shaft 105, and an end tool slide 112 shiftable in a direction parallel with the driving shaft 105 (i.e., in a lateral direction in FIG. 4), these slides 111 and 112 being selectively arranged in accordance with the feeding direction of the processing tool 113 loaded on these slides for the lathe turning operation.
The cross tool slide 111 is attached to the side of the head stock 101, whereas the end tool slide 112 is attached to the side of the column 103 towards which the head stock 101 faces.
The processing tools 113, 113' loaded on these tool slides are used in the lathe-turning, milling, drilling and thread-forming operations and the like to be performed on the workpieces, and a cutter 113' is shown loaded on the end tool slide 111 in the illustrated embodiment, whereas a rotary tool 113 such as a drill and the like is shown loaded on the end tool slide 112.
In the multi-spindle automatic lathe constituted as above, a workpiece W is previously contained on a stock reel 114 provided in the rearward (in the leftward direction in FIG. 4) of the multi-spindle automatic lathe, and then the workpiece W is caused to penetrate through the spindle 107 freely rotatably attached on the spindle carrier 102 and projects into a tooling zone 115 defined between the head stock 101 and the column 103. The workpiece W is subject to various machining operations whenever the spindle carrier 102 makes a rotary indexing movement.
In the traditional multi-spindle automatic lathe of the type as described and illustrated in FIGS. 4 and 5, while the cross tool slide 111 movable in the direction in which it may intersect with the axis of the spindle 107 is mounted on the side of the head stock, the end tool slide 112 shiftable in a direction in parallel with the axis of the spindle 107 is arranged at the side of column 103 facing head stock 101 with the tooling zone sandwiched therebetween.
Consequently, an operator had to frequently access the multi-spindle automatic lathe from its front or back portions to replace the processing tool 113 when required to load or unload the processing tool 113 relative to each of the tool slides 111 and 112. This produces a problem significantly reducing operating efficiency.
Moreover, because a separate feed driving mechanism is provided for each of the tool slides 111 and 112 independently on head stock 101 and column 103, there was another problem that the entire lathe was enlarged in dimensions. Furthermore each of the tool slides 111 and 112 can merely move in a single direction with a result that the processing freedom of the lathe was limited.
Thus, for the multi-spindle automatic lathe having a plurality of spindles which are parallel each other, it has been desirable that each of the tool slides and a feed driving mechanism which affords a feeding movement to the tool slides are designed to be compact as much as possible in order to facilitate exchanging the processing tools and ensuring an easy removal of chips.
In particular, a tool slide and its driving mechanism with a compact construction is in desperate need for the traditional multi-spindle automatic lathe, where respective tool slides must be arranged on a plurality of spindles each of which is arranged in an annular configuration, because such a lathe inherently does not allow an ample operating space.